The present invention relates to thermal printing systems and, more particular, to a thermal printing postage meter having a thermal transfer ribbon cassette.
In a novel thermal printing postage arrangement a line matrix thermal print head is employed. It is considered advantageous to use thermal ribbon cassette in combination with a rotating platen. Generally, a suitable configuration includes a postage meter base having an envelope transport which include a rotatively driven platen. The line matrix thermal print head and thermal ribbon cassette are mounted to the base such that the envelope is captured between the platen roller and the thermal ribbon with the thermal print head serving as a backing. The platen roller applies a basing force such that rotation of the platen roller cause the envelope to travel in the print direction. The platen action is used to drive both the envelope and cassette ribbon past the thermal print head in this manner the opportunity for print smearing is minimized.
In order to monitor the printing process, it is advantageous to provide some means of verifying the print speed. In this context, the actual print speed may vary from the set print speed as a function of envelope thickness.